MPs have urged the government to set out its plans to protect households from high energy bills this winter as they said about 1.7 million people, including some of the most vulnerable groups, had been left waiting too long to receive previous support.
The public accounts committee (PAC) said that although schemes were introduced quickly, the government "did not have the bandwidth" to make sure help reached all groups in a timely fashion.
The cross-party group said it had "serious concerns" about the Department for Energy Security and Net Zero's (DESNZ) "lack of urgency in addressing the energy market failures that are leading to high energy bills for consumers".
PAC's chair, Meg Hillier, said: "The surge in energy prices has caused serious difficulties and hardship for households across the UK. It is of course welcome to see government moving quickly to put in place support for both households and businesses to keep the lights on. But many of those who most needed help were kept waiting longest for it. For some households, every day left without support presented impossible choices."
The committee urged the government to provide an update on its plans to ensure there is affordable energy for households this winter.
Hillier said: "Almost halfway through the year, we have not yet seen plans to ensure energy affordability for the coming winter. As a matter of urgency, government must show it is clear not just on how households and businesses will be protected in any future price rises, but how to ensure resilience in the sector as a whole."
About 900,000 households without a direct relationship to a domestic energy supplier, such as those in park homes or living on boats, became eligible for the energy bill support scheme only in late February, almost five months after consumers began receiving discounts on the main scheme.
About 830,000 households in Northern Ireland began receiving support with their energy bills in January.
By the end of April, £160m of energy support vouchers for households using traditional prepayment meters had not been redeemed.
In February, DESNZ estimated support for households and businesses would cost £69bn, of which £16bn was paid between October and December 2022.
A DESNZ spokesperson said: "Today's report fails to recognise the complexities of delivering support to households without a direct relationship with a supplier - and it is right we made sure there was a robust system to help protect people against fraud before rolling it out."
He said millions received help within weeks and 83% of energy bill support vouchers had now been redeemed.